This invention relates to a single handle mixer valve with hard material plates, of the type wherein the movable plate is mounted swingable around a fulcrum.
Among the various possibilities in mounting and guiding the movable plate of a single handle mixer valve with hard material plates, it is known that said plate may be mounted swingable around a fulcrum. This kind of installation is preferred for certain applications, and among its advantages it is to be remembered that the limited displacement extension of the swingable plate aids in maintaining a layer of lubricating grease between the fixed plate and the movable plate, thus ensuring a quiet and regular operation of the valve for a sufficiently long period of time.
In the known embodiments, the movable plate has a tail portion guided in a casing which encloses the valve mechanisms, thus forming a fulcrum; or the movable plate has a projectiong tooth, forming a fulcrum, which engages a fixed guide member; or even the movable plate has a slit engaged by a fixed tooth forming a fulcrum. However such embodiments need relatively complicated shapes of the movable plate, whose manufacturing costs are therefore increased. Moreover, in most cases, with this kind of swingable plates, there are difficulties in providing the valve with preclosure means. Preclosure means are desirable in order to attain a more gradual behaviour of the valve, particularly when reduced flows are delivered, and in order to reduce the noise produced by the valve.